CPM Homework Help : A2C Problem 12-64

Write each series in sigma notation and find the sum or an expression for the sum. Homework Help ✎
1. 47 + 34 + 21 + … + (−83)
2. 3+10 + 17 + … + (7n − 4)

Hint (a):

What is the expression for the sequence?

More Help (a):

How many terms are there in the series?

Answer (a):

One possible answer:

$\sum_{k = 1}^{11}(60-13k)=-198$

Hint (b):

Instead of going up to a specific term, this series sums up the first n terms of the sequence given in parentheses.